Morphology control in the synthesis of [Mo3S13]2−/Co-MOF-74 composite catalysts and their application in the oxygen evolution reaction

Abstract

The novel composite electrocatalysts [Mo₃S₁₃]²⁻/Co-MOF-74 have been successfully prepared by using a simple solvothermal method. The morphology of composite catalysts can be effectively controlled by regulating the amount of [Mo₃S₁₃]²⁻ because the addition of [Mo₃S₁₃]² can affect the nucleation rate of Co-MOF-74. After the optimization, [Mo₃S₁₃]²⁻/Co-MOF-74 with spindle-like morphology displays remarkable OER electrocatalytic activity with a low overpotential (368 mV) to afford the current density of 10 mA cm⁻² and a small Tafel slope of 90.6 mV dec⁻¹, which is almost on a par with IrO₂/C (358 mV, 89.1 mV dec⁻¹). Besides, this composite catalyst can continuously work for about 17 h with almost negligible attenuation in current density. Such an excellent electrocatalytic OER performance of [Mo₃S₁₃]²⁻/Co-MOF-74 benefits from the good morphology obtained by the introduction of a moderate amount of [Mo₃S₁₃]²⁻ as well as the synergistic effect between the [Mo₃S₁₃]²⁻ and Co-MOF-74. This work provides new insight into the development of MOF-based electrocatalysts for the OER.